I am an active and concerned parent, who enjoys gaming with my children. Currently, the PlayStation 3's parental controls are thorough, but flawed. I have some suggestions that would significantly reduce mine and my children's frustrations:
1) Institute a numeric code which could be hidden from view (i.e. triangle=1, square=2, circle=3, etc). Currently my children have to leave the room every time I unlock a game for us to play together.
2) Allow the parental control of individual games to be manually overwritten (from the 'information' screen). If I could move games I find appropriate from a level 5 to a level 4, or move some inappropriate games from level 3 or level 4 to a level I feel more appropriate, it would give far greater control over my family's access.
3) Allow an 'unlock window' where the whole system could be unlocked for 2 hours at a time, making switching games easier and reducing the number of parental control pin inputs necessary. Right now, going to the menu to unlock the system, then returning to the menu later to re-lock it is a bit annoying.
4) Allow time constraints to be put on when the system could be used - effectively locking the system out entirely at some points of the day
Most of these improvements appear to be relatively simple to code, and would GREATLY increase the 'family friendly' capabilities of your system, putting it on par or better than other consoles.